U.S. Pat. No. 6,286,279, Method for Attaching Fabric and Floor Covering Materials to Concrete, to Bean et al., Sep. 11, 2001, and incorporated herein by reference, teaches bonding a thin metal plate or metal foil to a concrete surface to effect a barrier to water vapor transfer. The configuration of the '279 patent improves the maintenance of the bond between a concrete surface and various types of floor coverings. The '279 patent teaches two systems for implementing the barrier: one uses a single-layered thin metal plate or metal foil that is folded to produce recesses much like corrugated sheet metal. One side of the foil is attached to the concrete surface using a Portland cement-based thin set grout. A second embodiment employs a two-part thin metal plate or foil. A first lower part is perforated (or slit and expanded) and attached to a second solid upper part. The lower perforated part is embedded in a layer of thin set mortar on the concrete to anchor it to the concrete. The thin set mortar that oozes through the perforations also serves as a mechanical bond, a “cementitious rivet,” supplementing the chemical bond made along the contact surface.
A preferred embodiment of the present invention is an improvement on the '279 patent in that it allows the thin metal plate or metal foil to be embedded just below the surface of the underlayment, concrete in the case of a “poured slab,” so that there is a layer, e.g., concrete, both above and below the thin metal plate or metal foil. That is, a robust “finish” surface, e.g., concrete, is placed above the thin metal plate or metal foil, thus presenting a durable surface of conventional appearance. One advantage of this design is the ability of the surface to resist moisture flow from without while accommodating typical use, e.g., that of hard-wheeled vehicles that would otherwise damage vinyl or carpet floor coverings.